Java Utililty Methods Year Week

String getEndDayByWeekOfYear(int year, int weekNo)
get the end day of given week no of a year.,the first day of week is Sunday

Calendar cal = getCalendarFormYear(year);
cal.set(Calendar.WEEK_OF_YEAR, weekNo);
cal.add(Calendar.DAY_OF_WEEK, 6);
int monthInt = cal.get(Calendar.MONTH) + 1;
String monthString = monthInt < 10 ? "0" + monthInt : monthInt + "";
int dayOfMontyInt = cal.get(Calendar.DAY_OF_MONTH);
String dayOfMonth = dayOfMontyInt < 10 ? "0" + dayOfMontyInt : dayOfMontyInt + "";
return cal.get(Calendar.YEAR) + "-" + monthString + "-" + dayOfMonth;
...

Date getLastDayOfWeek(int year, int week)
get Last Day Of Week

Calendar cal = Calendar.getInstance();
cal.set(Calendar.YEAR, year);
cal.set(Calendar.MONTH, Calendar.JANUARY);
cal.set(Calendar.DATE, 1);
Calendar c = (Calendar) cal.clone();
c.add(Calendar.DATE, week * 7);
return getEndTimeOfWeek(c.getTime());

String getLastWeekOfYear()
get Last Week Of Year

int num = Calendar.getInstance().get(Calendar.WEEK_OF_YEAR);
if (num > 1) {
 num--;
return (num + "").length() == 1 ? "0" + num : "" + num;

int getMaxWeekNumOfYear(int year)
get Max Week Num Of Year

Calendar c = new GregorianCalendar();
c.set(year, Calendar.DECEMBER, 31, 23, 59, 59);
return getWeekOfYear(c.getTime());

Date getNextWeekMonday(int year, int weekOfYear)
get Next Week Monday

Date date = getMondayOfWeek(year, weekOfYear);
return getNextWeekDate(date);

int getNumberOfWeeksInYear(int year)
Computes the number of weeks in a given year See: http://stackoverflow.com/questions/18438332/how-to-get-total-number-of-week-in-the-current-year

GregorianCalendar cal = new GregorianCalendar(year, 12, 31);
cal.setFirstDayOfWeek(Calendar.MONDAY); 
cal.setMinimalDaysInFirstWeek(4); 
return cal.getMaximum(Calendar.WEEK_OF_YEAR);

int getSeasonStartWeekOffset(int year)
get Season Start Week Offset

Calendar cal = Calendar.getInstance();
cal.set(Calendar.YEAR, year);
cal.set(Calendar.MONTH, Calendar.SEPTEMBER);
cal.set(Calendar.DAY_OF_MONTH, 1);
switch (cal.get(Calendar.DAY_OF_WEEK)) {
case Calendar.SUNDAY:
 return 34;
case Calendar.MONDAY:
...

String getStartDayOfWeekNo(int year, int weekNo)
get start date of given week no of a year

Calendar cal = getCalendarFormYear(year);
cal.set(Calendar.WEEK_OF_YEAR, weekNo);
return cal.get(Calendar.YEAR) + "-" + (cal.get(Calendar.MONTH) + 1) + "-" + cal.get(Calendar.DAY_OF_MONTH);

int getTotalWeekOfYear(int year)
get Total Week Of Year

Calendar c = Calendar.getInstance();
return c.getActualMaximum(Calendar.WEEK_OF_YEAR);

String getYmd(int year, int week, int days)
get Ymd

Calendar calendar = Calendar.getInstance();
if (year > 0) {
 calendar.set(Calendar.YEAR, year);
calendar.set(Calendar.WEEK_OF_YEAR, week);
calendar.set(Calendar.DAY_OF_WEEK, days);
int month = calendar.get(Calendar.MONTH) + 1;
int day = calendar.get(Calendar.DAY_OF_MONTH);
...